JP5928974B2 - Reactor, converter, and power converter - Google Patents

Description

  The present invention relates to a reactor used as a component of a power conversion device such as an in-vehicle DC-DC converter mounted on a vehicle such as a hybrid vehicle, a converter including the reactor, and a power conversion device including the converter. Is. In particular, the present invention relates to a reactor having high bonding strength between a coil and a case and excellent heat dissipation.

  A reactor is one of the parts of a circuit that performs a voltage step-up operation or a voltage step-down operation. For example, Patent Document 1 discloses, as a reactor used in a converter mounted on a vehicle such as a hybrid car, a coil having a pair of coil elements, an annular magnetic core in which the coil is arranged and forms a closed magnetic circuit, A device including a box-shaped case that houses a combination of a coil and a magnetic core, and a sealing resin filled in the case is disclosed. In this reactor, a sealing resin is filled between the bottom surface of the case and the surface on the case side of the coil, and this sealing resin is used for insulation between the case and the coil. In addition, this reactor proposes to form an insulating thin film coating on the inner bottom surface of the case in order to further improve the insulating properties.

  A reactor for in-vehicle use or the like is fixed to an installation target such as a cooling base and is cooled during use. Therefore, the reactor case is typically made of aluminum or an alloy thereof so that it can be used as a heat dissipation path (specification 0024 of Patent Document 1). Further, Patent Document 1 discloses a configuration in which a magnetic core support portion is provided on the bottom surface of the case to radiate heat from the magnetic core through the case.

JP2009-099596

A further improvement in heat dissipation is desired over conventional reactors.
In the reactor, since the coil generates heat when energized, it is desired to efficiently transfer the heat of the coil to the installation target. In the reactor of Patent Document 1, since the sealing resin is interposed between the coil and the case, it is excellent in insulation, but it is difficult to further improve the heat dissipation.

Further, a reactor having a conventional case is inferior in assembling workability.
Since the coil is typically made of copper, and the magnetic core is typically made of iron or steel, the combination of the coil and the core is heavy. In the conventional reactor, the combination of the heavy objects must be inserted from the opening above the case, and the assembly workability is poor.

  The inventors of the present invention have studied a configuration in which the case is divided into a bottom plate portion and a side wall portion, each of which is a separate member, the bottom plate portion is made of a metal material, and the coil is joined to the bottom plate portion. By making it a separate member, the above-mentioned assembly can be easily placed on the bottom plate part, and after placing the combination, the bottom plate part is assembled to the side wall part so that the combination is housed in the case. it can. Therefore, this structure can reduce the burden accompanying the movement of heavy objects and is excellent in assembling workability. In addition, the bottom plate portion is generally made of metal having excellent thermal conductivity, and the structure in which the coil is directly joined to the bottom plate portion can shorten the distance between the coil and the bottom plate portion. Enhanced.

  However, as a result of investigations by the present inventors, in the above configuration, it has been found that when the adhesive is directly disposed on the bottom plate portion, the coil and the bottom plate portion may be peeled off. The reason for this is considered that a natural oxide film or the like is formed on the surface of the bottom plate portion, which may impede the adhesion between the bottom plate portion and the adhesive. And by this peeling, the heat of a coil cannot be efficiently transmitted to an installation object via a bottom plate part, and a heat dissipation is reduced.

  Therefore, one of the objects of the present invention is to provide a reactor having high bonding strength between a coil and a case and excellent heat dissipation. Another object of the present invention is to provide a converter including a reactor having excellent heat dissipation and a power converter including the converter.

  According to the present invention, the case is not a molded product in which the bottom plate portion and the side wall portion are integrally molded, but the bottom plate portion and the side wall portion are separated from each other, and the coil is formed on the metal bottom plate portion via a bonding layer. The above-mentioned object is achieved by adopting a configuration in which a treatment for improving the adhesion between the bottom plate portion and the bonding layer is performed.

  The reactor of the present invention includes a coil, a magnetic core in which the coil is disposed, and a case that houses a combination of the coil and the magnetic core. The case includes a bottom plate portion, a side wall portion that is a member independent of the bottom plate portion, and a bonding layer that is provided on the inner surface of the bottom plate portion and fixes the coil. The bottom plate portion is made of a metal material. The side wall portion is attached to the bottom plate portion and surrounds the periphery of the combination. The reactor is subjected to a surface roughening treatment on at least the region where the bonding layer is provided on the inner surface of the bottom plate portion.

  In the case provided in the reactor of the present invention, since the bottom plate portion and the side wall portion are separate members, the combination of the coil and the magnetic core is disposed on the bottom plate portion as described above, and then the bottom plate portion and the side wall portion are arranged. Can be integrated into a state in which the assembly is housed in the case. Moreover, this invention reactor can fix an assembly (coil) reliably with respect to a case by providing a joining layer irrespective of the presence or absence of sealing resin. Therefore, the reactor of the present invention is excellent in assembling workability as compared with the case of using a conventional integrally molded case.

  In the reactor of the present invention, the bottom plate portion is generally made of a material having excellent thermal conductivity: a metal material, and the coil is fixed to the bottom plate portion by a bonding layer. By arranging the coil close to the bottom plate portion by the bonding layer, the heat of the coil can be efficiently transmitted to the bottom plate portion. In particular, in the reactor of the present invention, the surface area of the bottom plate portion where the bonding layer is provided is roughened, so that a sufficiently large contact area between the bottom plate portion and the bonding layer can be secured. The bonding strength between the bottom plate portion and the bonding layer is high. Therefore, the bottom plate portion and the coil are firmly fixed via the bonding layer, so that the heat of the coil can be efficiently transmitted to the installation target via the bottom plate portion. From these points, the reactor of the present invention is excellent in heat dissipation.

  As one form of this invention reactor, the said roughening process is an anodizing process and the form which provides an anodized layer on the inner surface of the said baseplate part is mentioned.

  Anodizing treatment is easy to roughen a large amount of materials and large area materials, and is excellent in productivity. In addition, since an anodic oxide layer has many OH groups on its surface, it can form strong hydrogen bonds with the constituent material of the bonding layer, such as an adhesive, and thus has excellent adhesion to the bonding layer. In addition, by forming dimples having a diameter of about 3 μm to 400 μm on the surface of the anodized layer, the surface area can be increased by about 1.8 times compared to the case of only the bottom plate portion. The constituent metal of the bottom plate and the anodized layer have very high adhesion. From these things, the said form can raise joint strength of a baseplate part and a joining layer effectively through an anodic oxidation layer. Moreover, since the anodic oxidation layer is excellent in insulation, the said form can improve the insulation between a coil and metal bottom plate parts.

  As an embodiment having the anodized layer, there is an embodiment in which the thickness of the anodized layer is 2 μm or more and 20 μm or less.

  The anodized layer typically has a large number of very fine pores having a diameter of about 300 nm to 700 nm. In the form in which the thickness of the anodized layer is 2 μm or more, since the anodized layer has a sufficient thickness, there are deep micropores, and the contact area between the anodized layer and the bonding layer is large. In addition, the bonding strength between the anodized layer and the bonding layer, and thus the coil and the bottom plate can be increased. In addition, when the thickness of the anodized layer is within the above range, a decrease in thermal conductivity due to the presence of the anodized layer can be suppressed. Therefore, the said form is excellent in joining strength and heat dissipation.

  As an embodiment comprising the anodized layer, the anodized layer has a crack part extending from the surface to the metal material constituting the bottom plate part, and the crack part is filled with the constituent material of the bonding layer Is mentioned.

  As a result of investigations by the present inventors, when the anodized layer is formed to a certain extent (especially 9 μm or more, preferably 12 μm or more), the subsequent heat history (curing of the constituent material of the bonding layer (typically, an adhesive)) The cracks that reach the bottom plate part are generated in the anodized layer depending on the time and the sealing resin is cured, and the bonding layer is filled with the constituent material of the bonding layer, thereby further increasing the bonding strength. Obtained knowledge. In the above embodiment, by providing the crack portion filled with the constituent material of the bonding layer, in addition to the increase in the contact area with the bonding layer due to the fine holes and dimples in the anodized layer, The bonding strength is further increased by an increase in the contact area and an anchor effect due to being deeper than the fine holes and dimples.

  As one form of this invention reactor, the anodization layer is not provided in a part of said bottom-plate part, the said metal material is exposed, and the form whose this exposed part is an attachment location of a ground wire is mentioned. .

  The said form can perform a grounding work easily by having the attachment location of a ground wire.

  As one form of this invention reactor, the form by which the said side wall part was comprised with insulating resin is mentioned.

  Since the said form is excellent in the insulation between a coil and a side wall part, the distance between a coil and a side wall part can be shortened or made to contact, and size reduction of a reactor can be achieved. Moreover, the said form can achieve the weight reduction of a reactor because a side wall part is comprised with resin lightweight compared with a metal.

  As one form of this invention reactor, the form whose total thickness of the said joining layer is 2 mm or less is mentioned.

  In the above embodiment, since the thickness of the bonding layer is thin, the distance between the coil and the bottom plate portion is very short, and the heat of the coil can be efficiently transmitted to the installation object through the bottom plate portion, and the heat dissipation is excellent. Since the heat dissipation is improved as the thickness of the bonding layer is thinner, it can be 1 mm or less, and further 0.5 mm or less.

  The reactor of the present invention can be suitably used as a component part of a converter. The converter of the present invention comprises a switching element, a drive circuit that controls the operation of the switching element, and a reactor that smoothes the switching operation, and converts the input voltage by the operation of the switching element. The form whose reactor is this invention reactor is mentioned. This converter of the present invention can be suitably used as a component part of a power converter. The power converter of the present invention includes a converter that converts an input voltage and an inverter that is connected to the converter and converts between direct current and alternating current, and drives a load with the power converted by the inverter. And the converter is a converter according to the present invention.

  The converter of the present invention and the power conversion device of the present invention are excellent in productivity and heat dissipation by including the reactor of the present invention excellent in assembly workability, adhesion between the coil and the case, heat dissipation, etc., and suitable for in-vehicle parts and the like. Can be used.

  The reactor of the present invention has high bonding strength between the coil and the case, and is excellent in heat dissipation.

1 is a schematic perspective view showing a reactor of Embodiment 1. FIG. 1 is an exploded perspective view showing an outline of a reactor of Embodiment 1. FIG. FIG. 3 is an exploded perspective view schematically showing a combination of a coil and a magnetic core provided in the reactor of the first embodiment. FIG. 4 is a cross-sectional view taken along the line (IV)-(IV) in FIG. 1 in the reactor according to the first embodiment, where (A) shows the whole, and (B) and (C) show an enlarged vicinity of the bonding layer. It is a micrograph of the surface of the test piece used in Test Example 1, (A) is a test piece subjected to the roughening treatment (anodization treatment) used in Sample No. 1-2, (B), It is a test piece as the rolled material used for sample No.100. (A) is a photomicrograph of the surface of the test piece of sample No. 1-2 used in Test Example 1, and (B) shows an enlarged crack portion. (A) is a micrograph observing a cross section near the boundary between the bonding layer and the bottom plate in the reactor prototyped in Test Example 2, and (B) is a crack in the rectangular frame with white dotted lines in (A). The part is shown enlarged. 1 is a schematic configuration diagram schematically showing a power supply system of a hybrid vehicle. It is a schematic circuit diagram which shows an example of this invention power converter device which provides this invention converter.

  Hereinafter, a reactor according to an embodiment will be described with reference to the drawings. The same reference numerals in the figure indicate the same names. In the following description, when the reactor is installed, the installation side is described as the lower side, and the opposite side is described as the upper side.

Embodiment 1
≪Reactor overall structure≫
A reactor 1 according to a first embodiment will be described with reference to FIGS. The reactor 1 includes a coil 2, a magnetic core 3 in which the coil 2 is disposed, and a case 4 that houses a combined body 10 of the coil 2 and the magnetic core 3. The case 4 is a box having a bottom plate portion 40 (FIG. 2) and a side wall portion 41 standing from the bottom plate portion 40 and having an opening on the side facing the bottom plate portion 40. The features of the reactor 1 are (1) that the bottom plate portion 40 and the side wall portion 41 constituting the case 4 are not integrally formed and are separate separate members, and (2) the bottom plate portion 40 is a metal material. Comprising a bonding layer 42 (FIG. 2) for fixing the coil 2 on its inner surface 40i (FIG. 2), and (3) roughening the region of the bottom plate 40 where the bonding layer 42 is provided. It is in the processing. Hereinafter, each configuration will be described in more detail.

[coil]
The coil 2 will be described mainly with reference to FIGS. The coil 2 includes a pair of coil elements 2a and 2b formed by spirally winding a single continuous winding 2w having no joint part, and a coil connecting part 2r for connecting both the coil elements 2a and 2b. . Each coil element 2a, 2b is a hollow cylindrical body having the same number of turns, arranged in parallel (side by side) so that the respective axial directions are parallel, and wound on the other end side (right side in FIG. 3) of the coil 2 A part of 2w is bent into a U shape to form a coil coupling portion 2r. With this configuration, the winding directions of both coil elements 2a and 2b are the same.

  In addition, it can be set as the coil which produced each coil element by a separate coil | winding, and joined one end part of the coil | winding of each coil element by welding, soldering, crimping | compression-bonding, etc.

  As the winding 2w, a coated wire having an insulating coating made of an insulating material can be suitably used on the outer periphery of a conductor made of a conductive material such as copper, aluminum, or an alloy thereof. The conductor is typically a rectangular wire, and various other cross-sectional shapes such as a circular shape, an elliptical shape, and a polygonal shape can be used. The flat wire (1) has a high space factor, (2) it is easy to ensure a wide contact area with the bonding layer 42 provided on the bottom plate portion 40 described later, and (3) the contact area with the terminal fitting 8 described later. There is an advantage that it is easy to ensure widely. Here, the conductor is made of a copper rectangular wire, and the insulation coating is made of a coated rectangular wire made of enamel (typically polyamide imide) .Each coil element 2a, 2b turns this covered rectangular wire into edgewise winding. Edgewise coil. In addition, here, the end face shape of each of the coil elements 2a and 2b is a shape obtained by rounding the corners of the rectangle, but it can be appropriately changed such as a circular shape.

  Both ends of the winding 2w forming the coil 2 are appropriately extended from the turn forming portion on one end side (left side in FIG. 3) of the coil 2, and typically drawn out of the case 4 (FIG. 1). ). At both ends of the winding 2w, one end portion 81 of a terminal fitting 8 made of a conductive material such as copper, aluminum, or an alloy thereof is connected to a conductor portion exposed by peeling off the insulation coating by soldering, welding, or crimping. . An external device (not shown) such as a power source for supplying power is connected to the coil 2 via the terminal fitting 8. Note that the shape of the terminal fitting 8 shown in FIG. 2 and the like is merely an example, and the shape of the one end portion 81 can be changed as appropriate, for example, to be U-shaped instead of flat.

[Magnetic core]
The magnetic core 3 will be described with reference to FIG. The magnetic core 3 has a pair of inner core portions 31 covered with the coil elements 2a and 2b, and a pair of outer core portions 32 that are not disposed on the coil 2 and are exposed from the coil 2. Each inner core portion 31 is a columnar body having an outer shape along the inner peripheral shape of each coil element 2a, 2b (here, a shape obtained by rounding the corners of a rectangular parallelepiped), and each outer core portion 32 is respectively A columnar body having a pair of trapezoidal surfaces. In the magnetic core 3, both outer core portions 32 are disposed so as to sandwich a pair of spaced apart inner core portions 31, and the end surface 31e of each inner core portion 31 and the inner end surface 32e of the outer core portion 32 are in contact with each other. To form an annular shape. The inner core portion 31 and the outer core portion 32 form a closed magnetic path when the coil 2 is excited.

  The inner core portion 31 is a laminated body configured by alternately laminating core pieces 31m made of a magnetic material and gap members 31g typically made of a nonmagnetic material, and the outer core portion 32 is made of a magnetic material. A core piece consisting of

  As each core piece, a molded body using magnetic powder or a laminated body in which a plurality of magnetic thin plates (for example, electromagnetic steel sheets) having an insulating coating are laminated can be used. The molded body is, for example, an iron group metal, Fe-Si or Fe-Si-Al, an iron alloy such as steel, a powder molded body using a powder made of a soft magnetic material such as a rare earth metal or an amorphous magnetic body, and the above powder. And a molded hardened body (composite material) obtained by subjecting a mixture of the above powder and resin to injection molding or cast molding. In addition, examples of the core piece include a ferrite core that is a sintered body of a metal oxide. The molded body can be easily formed even with a complex solid core piece or magnetic core.

  The green compact is typically a powder made of the soft magnetic material, and after forming a coating powder having an insulating coating (such as silicone resin or phosphate) on the surface of each particle, heat treatment (preferably Can be produced by applying a temperature lower than the heat resistance temperature of the insulating coating. Here, each core piece is a compacted body of soft magnetic powder containing iron such as iron or steel.

  The gap material 31g is a plate-like member that is arranged between the core pieces and adjusts the inductance, and a material having a lower magnetic permeability than the core piece is used as a constituent material thereof. Typical constituent materials include nonmagnetic materials such as alumina, glass epoxy resin, and unsaturated polyester. In addition, if the gap material is made of a mixed material in which magnetic powder (for example, ferrite, Fe, Fe-Si, sendust, etc.) is dispersed in a nonmagnetic material such as ceramics or phenol resin, the leakage magnetic flux in the gap portion can be reduced. It can also be an air gap. Depending on the material of the core piece, a gapless configuration without a gap material can be obtained. The number of core pieces and gap members can be appropriately selected so that the reactor 1 has a desired inductance. Moreover, the shape of a core piece or a gap material can be selected suitably.

  For the integration of the core pieces and the integration of the core piece 31m and the gap material 31g, for example, an adhesive or an adhesive tape can be used. For example, an adhesive tape may be used to form the inner core portion 31, and the inner core portion 31 and the outer core portion 32 may be joined with an adhesive.

  Alternatively, the inner core portion 31 can be formed using an insulating tube such as a heat shrinkable tube or a room temperature shrinkable tube. In this case, the insulating tube also functions as an insulating material between the coil elements 2a and 2b and the inner core portion 31.

  In addition, the magnetic core 3 shown in this example has a surface on the installation side of the inner core portion 31 (lower surface in FIG. 3) and a surface on the installation side of the outer core portion 32 (hereinafter, referred to as a core installation surface). Instead, the core installation surface of the outer core portion 32 protrudes from the inner core portion 31, and is flush with the surface on the installation side of the coil 2 (hereinafter referred to as the coil installation surface). Therefore, the surface on the installation side of the combination 10 of the coil 2 and the magnetic core 3 is composed of the coil installation surfaces of both the coil elements 2a and 2b and the core installation surface of the outer core portion 32, and the coil 2 and the magnetic core 3 Both come into contact with a bonding layer 42 (FIG. 2) described later. Since the surface on the installation side of the combined body 10 is composed of both the coil 2 and the magnetic core 3, the contact area with the bottom plate 40 (FIG. 2) is sufficiently large, and the reactor 1 is stable when installed. Also excellent. Further, by configuring the core piece with a compacted body, a portion of the outer core portion 32 that protrudes from the inner core portion 31 can be used as a magnetic flux passage.

[Insulator]
The reactor 1 shown in this example further includes an insulator 5 interposed between the coil 2 and the magnetic core 3. By providing the insulator 5, the reactor 1 can enhance the insulation between the coil 2 and the magnetic core 3.

  As shown in FIG. 3, the insulator 5 is a pair interposed between a peripheral wall portion 51 disposed on the outer periphery of the inner core portion 31, and end faces of the coil elements 2a and 2b and an inner end face 32e of the outer core portion 32. Frame plate portion 52.

  The peripheral wall portion 51 is a member that insulates between the coil elements 2a and 2b and the inner core portion 31, and is a pair of cross sections that are divided in the direction perpendicular to the axial direction of the inner core portion 31 (vertical direction in FIG. 3). It can be easily arranged on the outer periphery of the inner core portion 31. Here, when the peripheral wall 51 is disposed on the inner core part 31, the outer peripheral surface of the inner core part 31 is not covered completely, but a part thereof is exposed, but when the divided pieces are combined, the inner core part The split piece may be configured to be a cylindrical body covering the entire circumference of 31, and the shape can be changed as appropriate.

  Each frame plate portion 52 is a B-shaped flat plate member having a pair of openings (through holes) into which the respective inner core portions 31 can be inserted. Here, the frame plate portion 52 includes a partition plate 52b in the middle of both openings, and when the frame plate portion 52 is assembled to the coil 2, the partition plate 52b is interposed between the coil elements 2a and 2b, The insulation between the coil elements 2a and 2b is improved. Also, one (right side in FIG. 3) frame plate portion 52 includes a pedestal 52p on which the coil coupling portion 2r is placed and insulates between the coil coupling portion 2r and the outer core portion 32.

  The shape of the insulator can be selected as appropriate. In addition to the form in which the peripheral wall part 51 and the frame plate part 52 are separate as described above, a form in which a cylindrical piece constituting the peripheral wall part is integrally formed on the frame plate part can be mentioned. This form is composed of a pair of divided pieces (consisting of the above-mentioned integral molded product) that can be divided in the axial direction of the coil 2. If each divided piece has an engaging portion that engages with each other, the mutual positioning can be facilitated. Alternatively, the peripheral wall portion 51 is omitted and only the frame plate portion 52 is provided, and another insulating coating layer is formed on the outer periphery of the inner core portion 31 (for example, formed by winding the above-described insulating tube, insulating tape, or insulating paper). It can be set as the form which comprises.

  As the constituent material of the insulator 5, insulating materials such as polyphenylene sulfide (PPS) resin, polytetrafluoroethylene (PTFE) resin, polybutylene terephthalate (PBT) resin, and liquid crystal polymer (LCP) can be used. For forming the insulator 5, a molding method such as injection molding can be suitably used.

[Case]
Case 4 will be described with reference to FIG. The case 4 includes a flat bottom plate portion 40 and a frame-like side wall portion 41 standing on the bottom plate portion 40, and the bottom plate portion 40 and the side wall portion 41 are separate members as described above.

(Bottom plate)
The bottom plate portion 40 is typically arranged so that one surface thereof is in contact with the installation target when the reactor 1 is installed on the installation target such as a cooling base, and the one surface is used as a cooling surface. The bottom plate portion 40 only needs to have an area where the combined body 10 of the coil 2 and the magnetic core 3 can be placed and to which the side wall portion 41 can be attached, and the outer shape (planar shape) is appropriately selected. be able to. Here, the bottom plate portion 40 is a rectangular plate and has a shape having attachment portions 400 protruding from the four corners.

  Each mounting portion 400 is provided with a bolt hole 400h through which a bolt (not shown) for fixing the case 4 to an installation target such as a cooling base is inserted. Here, the bolt hole 400h is provided so as to be continuous with a bolt hole 411h of the side wall 41 described later. As the bolt holes 400h and 411h, any of through holes that are not threaded and screw holes that are threaded can be used, and the number and the like can be appropriately selected. Reactor 1 is fixed so that bottom plate portion 40 is in contact with an installation object by bolts (not shown) arranged in bolt holes 400h and 411h.

(Sidewall)
The side wall portion 41 is a rectangular frame-like body, and when the case 4 is assembled by closing one opening portion with the bottom plate portion 40, the side wall portion 41 is disposed so as to surround the periphery of the assembly 10 of the coil 2 and the magnetic core 3. The other opening is opened. Here, the outer shape of the side wall 41 is a shape in which the opening side region (the upper region in FIG. 2) is along the outer peripheral surface of the combined body 10 (a combination of a plane and a curved surface), and the reactor 1 is the installation target. The region that is the installation side when installed (the lower region in FIG. 2) is a step shape that protrudes outward from the opening-side region, and a shape that follows the outer shape of the bottom plate portion 40. The shape of the side wall portion 41 can be changed as appropriate. For example, the side wall portion 41 can be a simple rectangular frame or a shape including the mounting portion 411 on the rectangular frame.

  Here, in the opening side region of the side wall portion 41, a bowl-shaped portion is provided so as to cover the trapezoidal surface of each outer core portion 32 of the combined body 10. In the combination 10 housed in the case 4 by these hooks, the coil 2 is exposed as shown in FIG. 1, and the magnetic core 3 is substantially covered with the constituent material of the case 4. By providing a hook-shaped part, (1) improved vibration resistance, (2) improved rigidity of the case 4 (side wall part 41), (3) magnetic core 3 (outer core part 32) from the external environment Various effects such as protection and mechanical protection, (4) prevention of the assembly 10 from falling off (stopping), and (5) use as a terminal block 410 described later can be obtained. If one or both of the hook-shaped portions are omitted and both the coil 2 and the trapezoidal surface of the one or both outer core portions 32 are exposed, the side wall portion 41 can be made a simpler shape.

  Here, the hook-shaped portion on one side (left side in FIG. 2) is used for the terminal block 410. This hook-shaped portion includes a concave groove 410c into which a pair of terminal fittings 8 to which respective end portions of the winding 2w are respectively connected. The terminal fitting 8 is disposed in the concave groove 410c, a part (intermediate portion) of the terminal fitting 8 is covered with the terminal fixing member 9, and the terminal fixing member 9 is tightened with the bolt 91, whereby the terminal fitting 8 is fixed to the side wall portion 41, A terminal block 410 can be formed.

  When the side wall 41 is made of an insulating resin, instead of using the terminal fixing member 9 and the bolt 91, the side fitting, the terminal fitting 8, and the terminal block are integrated by insert molding the terminal fitting 8. It can be in the form. In this embodiment, the number of parts and the number of assembly processes are small, and the productivity of the reactor is excellent.

  Similar to the bottom plate portion 40, the region on the installation side of the side wall portion 41 includes mounting portions 411 protruding from the four corners, and each mounting portion 411 is provided with a bolt hole 411h to constitute a mounting location. Yes. When the case 4 is formed by combining the bottom plate portion 40 and the side wall portion 41, the mounting portion 400 of the bottom plate portion 40 and the mounting portion 411 of the side wall portion 41 overlap. The bolt hole 411h may be formed only by the constituent material of the side wall portion 41, or may be formed by arranging a cylindrical body made of another material. For example, when the side wall portion 41 is made of resin, it is excellent in strength when a metal tube made of metal such as brass, steel, and stainless steel is used as the cylindrical body, and creep deformation compared to the case where the side wall portion 41 is made of resin alone. Can be suppressed. Here, a metal tube is arranged to form the bolt hole 411h.

  Here, both the bottom plate portion 40 and the side wall portion 41 are provided with the mounting portions 400, 411, but only the bottom plate portion 40 is provided with the mounting portion 400, and only the side wall portion 41 is provided with the mounting portion 411. can do. In the former form, the attachment part 400 is formed so that the attachment part 400 of the bottom plate part 40 protrudes from the outer shape of the side wall part. In the latter form, the bottom plate part is, for example, a rectangular plate, and the attachment part 411 of the side wall part 41. The outer shape of the side wall portion 41 is formed so as to protrude from the outer shape of the bottom plate portion.

(Material)
Since the bottom plate portion 40 and the side wall portion 41 are separate members, each can be made of a different material. In the present invention, the constituent material of the bottom plate portion 40 is a material having a high thermal conductivity such as a metal material so that the bottom plate portion 40 can be used as a heat dissipation path.

  Specific metals include, for example, aluminum (thermal conductivity: 237 W / m ・ K) and its alloys, magnesium (156 W / m ・ K) and its alloys, copper (398 W / m ・ K) and its alloys, silver ( 427W / m ・ K) and its alloys, titanium (21.9W / m ・ K) and its alloys, iron (80W / m ・ K), austenitic stainless steel (for example, SUS304: 16.7W / m ・ K), etc. Can be mentioned. In particular, aluminum and its alloys are lightweight and have excellent corrosion resistance. Magnesium and its alloys are further lightweight and have excellent vibration damping properties, and thus can be suitably used for in-vehicle components. Titanium and its alloys are relatively light and have excellent strength and corrosion resistance. In addition, aluminum, magnesium, titanium, and alloys thereof can use an anodizing treatment for the roughening treatment described later, and are excellent in workability of the roughening treatment. Copper, silver, and alloys thereof can be a reactor having excellent thermal conductivity and excellent heat dissipation. Iron and its alloys are excellent in strength and corrosion resistance. In particular, if the constituent material of the bottom plate portion 40 is a nonmagnetic metal such as aluminum or magnesium, even if the coil 2 is disposed close to the bottom plate portion 40, it is difficult to exert a magnetic influence.

  The bottom plate portion 40 can be manufactured in a desired shape by casting such as die casting. In addition, the bottom plate portion 40 can be manufactured by pressing (typically punching) or cutting a rolled material obtained by rolling the cast material into a desired shape.

  Examples of the constituent material of the side wall portion 41 include a material excellent in electrical insulation and heat resistance. An example of such a material is an insulating resin. Specifically, acrylonitrile-butadiene-styrene (ABS) resin, PBT resin, PPS resin, polypropylene (PP), polystyrene (PS), polyethylene (PE), polyethylene terephthalate (PET), polycarbonate (PC), polyacetal (POM) ), Thermoplastic resins such as acrylic, nylon 6, nylon 66, LCP, and urethane resin. Furthermore, if the resin contains at least one ceramic selected from silicon nitride, aluminum oxide (alumina), aluminum nitride, boron nitride, mullite, and silicon carbide, it has excellent insulation and heat dissipation. Enhanced.

  Alternatively, the constituent material of the side wall portion 41 can be the above-described metal material (particularly nonmagnetic metal). When the side wall portion 41 is also made of a metal material, heat dissipation and strength can be further enhanced.

  Here, the bottom plate portion 40 is made of an aluminum alloy, and the side wall portion 41 is made of PPS resin. Therefore, the reactor 1 has a thermal conductivity of the bottom plate portion 40 that is sufficiently higher than that of the side wall portion 41 and is excellent in heat dissipation. In addition, here, the coil 2 and the side wall 41 are placed close to each other, and the distance between the outer peripheral surface of the coil 2 and the inner peripheral surface of the side wall 41 is very narrow, about 0 mm to 1.0 mm. Excellent. Even when the coil 2 and the side wall portion 41 are close to each other, the side wall portion 41 is made of an insulating resin as described above, so that the insulating property is excellent.

(Consolidation method)
In order to integrally connect the bottom plate portion 40 and the side wall portion 41, various fixing materials can be used. Examples of the fixing member include an adhesive and a fastening member such as a bolt. Here, a bolt hole (not shown) is provided in the bottom plate portion 40 and the side wall portion 41, a bolt (not shown) is used as a fixing member, and the bolts are screwed together to integrate them.

(Roughening treatment)
One feature of the present invention is that at least a part of the surface of the bottom plate portion 40 made of a metal material, specifically, a formation region of a bonding layer 42 described later is subjected to a roughening treatment. .

  The roughening treatment is a treatment for forming fine irregularities in order to increase the contact area between the bottom plate portion 40 and the bonding layer. Specific treatments include (1) anodizing treatment represented by anodizing, (2) needle-like plating, (3) planting of molecular bonding compounds, (4) groove processing by laser, (5) nano-order dimples Formation, (6) etching treatment, (7) sand blasting and shot blasting, (8) polishing, and (9) matting treatment with sodium hydroxide. The fine irregularities include, for example, those having a surface roughness Ra of 10 μm or less.

  The above (2) is a needle-like metal plating having a diameter of φ0.1 μm to 0.2 μm and a length of 2 μm to 3 μm on a metal base material (here, the bottom plate part 40; hereinafter the same regarding the description of the roughening treatment). (For example, nickel plating). By these needle-like objects, fine irregularities are formed. The above (3) is a process in which a reactive functional group (—OH) is attached to a metal substrate and then a molecular bonding compound is planted on the metal substrate by a known method. Fine irregularities are formed by the molecular bonding compound present on the surface of the metal substrate, and the molecular bonding compound provides excellent adhesion between the metal substrate and the resin (here, bonding layer 42; hereinafter the same applies in this column). The above (4) is a process of forming a groove having a width of about 50 μm and a depth of about 50 μm to 100 μm by appropriately scanning the surface of the metal substrate with a YAG laser (for example, scanning in a lattice pattern). is there. The width, depth, and shape of the groove can be appropriately selected so as to obtain the desired unevenness. The above (5) is a process of forming a very fine dimple by immersing the metal substrate in a known special treatment liquid, and can form very fine irregularities with excellent adhesion to the resin. . The above (6) is a process for forming irregularities by immersing and corroding the metal substrate in a processing liquid for etching (acid liquid or alkaline liquid). Unevenness can be formed only in a desired region using masking. Further, the size of the unevenness can be changed by adjusting the concentration, type, immersion time, and the like of the etching solution. The above (7) is a process of forming irregularities by colliding particles of an appropriate material and size with the metal substrate. The above (8) is a process for forming irregularities by grinding the surface of the metal substrate using a known scissors. The above (9) is a process in which the metal substrate is dipped in a sodium hydroxide solution to roughen the surface of the metal substrate to form irregularities, and a known matting process can be used. In the treatments (2) to (9), known conditions, commercially available treatment liquids, and techniques that are performed on the metal materials described above can be used as appropriate.

  The anodizing treatment of (1) above is, for example, JIS H 8601 (1999) appendix 2 (reference) for aluminum and its alloys, JIS H 8651 (2011) for magnesium and its alloys, etc. For titanium and its alloys, it can be carried out with reference to JIS W 1108 (2000), and any known conditions can be used. In anodizing treatment, depending on conditions, a porous layer having a dense layer called a barrier layer on the metal substrate side and a plurality of fine pores (typically about 300 nm to 700 nm in diameter) on the dense layer. An anodized layer can be formed. Irregularities can be formed by these fine holes or dimples having a diameter of about 3 μm to 400 μm existing on the surface of the anodized layer.

  Anodizing treatment can be (1) roughening multiple materials or large materials at once, (2) thickness of anodized layer and uneven state (depth, number of dimples, dimples, etc.) depending on conditions (3) Since there are many OH groups on the surface, hydrogen bonding is possible due to intermolecular force, so it has excellent adhesion to the resin. (4) Insulation can be enhanced by the anodized layer. There are advantages such as.

  The thickness of the anodized layer can be selected as appropriate, but is preferably 2 μm or more. Here, the micropores usually do not reach the metal substrate due to the presence of the barrier layer described above. However, if the thickness of the anodic oxide layer is 2 μm or more, particularly more than 3 μm, the depth of the micropores becomes sufficiently deep, and the contact area with the constituent material of the bonding layer 42 can be increased. Therefore, the adhesion between the anodized layer and the bonding layer 42 can be enhanced by the dimples and the fine holes, and as a result, the bonding strength between the coil 2 and the bottom plate portion 40 can be improved.

  Furthermore, as a result of investigations by the present inventors, when the anodized layer is made thick to some extent, the subsequent thermal history causes a network-like crack in the anodized layer, in particular, a deep crack reaching the metal substrate. In a form in which the crack is filled with a constituent material (typically a resin such as an adhesive) of the bonding layer (typically a resin such as an adhesive), and an anodized layer in which there is a crack filled with the constituent material of the bonding layer, The knowledge that joint strength with a baseplate part increases was acquired. Also from this point, the anodized layer is preferably 9 μm or more, and more preferably 12 μm or more. However, if the anodic oxide layer is too thick, the heat dissipation is reduced, so that it is preferably 20 μm or less, more preferably 15 μm or less. When the anodized layer is 20 μm or less, the total thickness with a bonding layer 42 described later can be 2 mm or less, further 1.5 mm or less, and particularly 1 mm or less. The thickness of the anodized layer, the number / depth of micropores, and the number / depth / size (diameter) of dimples can be changed by adjusting the type of treatment liquid, the immersion time, the electrolysis voltage, and the like. Known conditions can be used as appropriate.

  Even if the above-mentioned crack does not reach the metal substrate, the presence of the crack in the anodized layer in addition to the above-described fine holes and dimples can increase the contact area with the constituent material of the bonding layer. . As the depth of the crack is deeper, the anchor effect by filling the constituent material of the bonding layer can be obtained. The presence or absence of cracks and the depth of cracks can be determined by observing the cross section of the bottom plate with an optical microscope or scanning electron microscope: SEM. The length of cracks can be determined by removing the bonding layer and examining the surface of the bottom plate with an optical microscope. Or by observing with SEM. The depth of the crack is preferably deeper than the depth of the fine holes, and more preferably the same as the thickness of the anodized layer, that is, it reaches the metal substrate. Further, it is considered that the contact area can be increased as the number of cracks increases or the length of cracks increases. The number, length, and depth of cracks vary depending on the thermal history after forming the anodized layer. When heat treatment is performed after the formation of the anodized layer, for example, if the heating temperature is increased, the holding time is increased, or the quenching process is performed from the heating temperature, the number of cracks tends to increase. After the bottom plate portion 40 is anodized, a heat treatment for crack formation may be separately performed, but when the bonding layer 42 is made of a material that needs to be thermally cured, this curing step is performed in a form having a sealing resin. When this sealing resin is a material that needs to be thermally cured, the curing process of the sealing resin can be used as a heat treatment for crack formation. As shown in a test example to be described later, when a somewhat thick anodic oxide layer is formed, cracks can be sufficiently formed by the above-described curing step.

  The region to be roughened in the bottom plate portion 40 can be appropriately selected as long as the region where the bonding layer 42 is provided is included. For example, the entire inner surface 40i of the bottom plate portion 40, the entire inner surface 40i and the side surfaces of the bottom plate portion 40, the inner surface 40i and the outer surface of the bottom plate portion 40, and the entire surface of the bottom plate portion 40 can be roughened. FIG. 4 illustrates a form in which the entire bottom plate portion 40 is provided with the anodized layer 43. In FIG. 4A, the side wall 41, the terminal fitting 8, and the like are omitted for easy understanding. 4 (B) and 4 (C), the region within the one-dot chain line circle in FIG. 4 (A) is shown enlarged, and the bonding layer 42 is highlighted (shown thick) for easy understanding.

  When the entire bottom plate 40 is subjected to a surface roughening treatment, no masking or the like is required for the surface roughening treatment that involves immersion in the treatment liquid (such as anodizing treatment or etching treatment). Work such as immersion in can be easily performed, and productivity is excellent. Among the roughening treatments, mechanical processing (processing using laser, sandblasting, etc.) can easily attach the ground wire and the like because the metal material is exposed even after the roughening treatment. When attaching the ground wire, the natural oxide film is appropriately removed. When the roughening process is performed on only a part of the bottom plate portion 40, depending on the type of the roughening process (for example, laser processing), the processing time is short and the productivity is excellent.

  When the surface roughening treatment is a treatment for forming a film having excellent insulating properties such as anodizing treatment, any part of the bottom plate 40 excluding the formation region of the bonding layer 42 is not subjected to the surface roughening treatment. (It is not provided with the said film | membrane), It can be set as the form which provides the exposed part from which the constituent metal of the baseplate part 40 was exposed. If this exposed location is, for example, a location where an earth wire is attached, the grounding operation can be performed easily. Further, for example, if the bottom plate portion 40 does not have an anodized layer on the outer surface in contact with the installation target and the metal material is exposed, it is expected that the heat dissipation can be improved.

(Junction layer)
Reactor 1 has a bonding layer 42 for fixing the coil 2 to the bottom plate portion 40 in the inner surface 40i of the bottom plate portion 40, in which the coil installation surface of the coil 2 is in contact with the roughened region. 2 and 4).

  The constituent material of the bonding layer 42 is a material that can fix the coil 2 to the bottom plate portion 40, typically, a resin such as an adhesive. The bonding layer 42 can be easily formed into a desired shape by, for example, applying an adhesive or the like to the bottom plate portion 40 that has been subjected to the above-described roughening treatment, or using screen printing or the like. Alternatively, the bonding layer 42 can be more easily formed by using a sheet-like adhesive cut into a desired shape. Screen printing and sheet adhesives are excellent in shape accuracy.

  As the adhesive layer 42, either a single-layer structure shown in FIG. 4C or a multilayer structure (here, a three-layer structure) shown in FIG. 4B can be used. In the case of a single layer structure, the bonding layer 42 can be very easily formed by using a sheet-like adhesive. In the multilayer structure, the constituent materials of the respective layers can be of different types in addition to the same type. For example, a multilayer structure including a layer having excellent electrical insulation and a layer having excellent heat dissipation and a layer having excellent adhesion can be obtained. The material is selected so that the layer has desired characteristics. The multilayer structure can be formed by, for example, forming the multilayer by the above-described screen printing or laminating the sheet-like adhesive in multiple layers.

  The constituent material of the bonding layer 42 is preferably an insulating resin, particularly an insulating adhesive (including a sheet-like one). Examples of the insulating resin include an epoxy resin and an acrylic resin. Furthermore, when an insulating resin containing a filler made of ceramics such as silicon nitride or alumina is used, the bonding layer 42 having excellent heat dissipation and electrical insulation can be formed.

  When the constituent material of the bonding layer 42 is an insulating material having a thermal conductivity of more than 2 W / m · K, it is possible to obtain a form excellent in heat dissipation and insulation. The higher the thermal conductivity, the better the heat dissipation, and the bonding layer is made of a material of 3 W / m · K or higher, especially 10 W / m · K or higher, more than 20 W / m · K, especially 30 W / m · K or higher. 42 may be configured. In the case where the bonding layer 42 is composed of a material containing the above-described filler, the material and content of the filler can be adjusted so as to have a desired thermal conductivity.

  As for the thickness of the bonding layer 42, the gap between the coil 2 and the bottom plate portion 40 can be reduced as the thickness (total thickness in the case of multiple layers, the same applies hereinafter) is reduced in both the single layer structure and the multilayer structure. The heat dissipation can be improved and the size can be reduced. The thicker the coil 2, the stronger the coil 2 is held, and when the insulating material is used, the insulation between the coil 2 and the bottom plate 40 is further improved. Can be achieved. For example, when the bonding layer 42 is made of an insulating material, the insulation between the coil 2 and the bottom plate 40 is ensured even if the thickness of the bonding layer 42 is 1 mm or less, and even 0.5 mm or less. Besides being thin, heat dissipation can be improved by being thin. Alternatively, when the bonding layer 42 is made of a material having excellent heat dissipation, the heat dissipation is sufficiently excellent even if the thickness of the bonding layer 42 is 0.5 mm or more, and further 1 mm or more.

  Note that the thickness of the bonding layer 42 described above is the thickness at the time of forming the bonding layer 42, and when the combination 10 of the coil 2 and the magnetic core 3 is placed on the bonding layer 42, In some cases, the thickness is less than 0.1 mm.

  The bonding layer 42 shown in FIG. 4 (B) is, for example, an epoxy adhesive (thickness: 0.1 mm) made of an epoxy adhesive (insulating adhesive) and an epoxy adhesive containing a filler made of alumina ( It has a total three-layer structure with two heat dissipation layers (thickness: 0.15 mm, thermal conductivity: 3 W / m · K) made of an insulating adhesive, and the total thickness is 0.4 mm. 4C is composed of, for example, a sheet-like adhesive made of an epoxy-based adhesive containing a filler made of alumina (thickness before curing: 0.4 mm, the combination 10 is mounted). (Thickness after placement: 0.1mm).

  The shape of the bonding layer 42 is not particularly limited as long as the coil installation surface of the coil 2 has an area that can be sufficiently contacted. Here, as shown in FIG. 2, the bonding layer 42 has a shape along the shape formed by the coil installation surface and the core installation surface of the outer core portion 32. For example, when an adhesive (including a sheet-like material) is used for the integration of the bottom plate portion 40 and the side wall portion 41, the adhesive and the constituent material of the bonding layer 42 are the same, and the bottom plate portion 40 If it arrange | positions at once, it is excellent in workability | operativity and is preferable. That is, the adhesive is disposed on the inner surface 40i of the bottom plate portion 40 by placing an adhesive on the installation region of the coil 2 (here, the installation region of the combination 10 of the coil 2 and the magnetic core 3) and the installation region of the side wall 41. A layer is formed, and a part of the adhesive layer is used for the bonding layer 42. Since this form can reduce the arrangement | positioning process and hardening process of an adhesive agent, it is excellent in productivity.

  In addition to the bonding layer 42, for example, an insulating sheet (not shown) may be provided. By providing the insulating sheet, it is possible to further improve the insulation between the coil 2 and the bottom plate portion 40.For example, the constituent material of the bonding layer 42 is made of an adhesive having a high adhesion force. Insulation can be secured by an insulating sheet. Examples of the insulating sheet include those composed of an insulating resin such as an amideimide resin, a polyimide resin, a polyester resin, and an epoxy resin. If the insulating sheet is thin, such as 0.5 mm or less, further 0.15 mm or less, particularly 0.1 mm or less, the total thickness of the bonding layer 42 and the insulating sheet is small, and the coil 2 and the bottom plate portion 40 are It is preferable because heat dissipation is improved. The insulating sheet can be brought into close contact with the bonding layer 42 or the bottom plate portion 40 by using a sheet having an adhesive layer on at least one side. When an insulating sheet including an adhesive layer is disposed immediately above the bottom plate portion 40 (roughened region), the adhesive layer of the insulating sheet is firmly joined to the roughened region. When the insulating sheet does not have an adhesive layer, for example, the bonding layer 42 may have a multilayer structure, and the insulating sheet may be interposed between the layers constituting the bonding layer 42. In this embodiment, the bonding layer 42 and the insulating sheet made of resin are firmly bonded, and the bonding layer 42 is firmly bonded to the surface-roughened region as described above.

[Sealing resin]
In addition, the case 4 may be filled with a sealing resin (not shown) made of an insulating resin. The filling amount of the sealing resin can be appropriately selected. For example, when the end of the winding is exposed from the sealing resin, the connection work with the terminal fitting 8 is easy to perform. A part of the coil 2 can be exposed from the sealing resin.

  Examples of the sealing resin include an epoxy resin, a urethane resin, and a silicone resin. Moreover, when it is set as the sealing resin containing the ceramic filler excellent in the insulation and thermal conductivity mentioned above, insulation and heat dissipation are further improved.

  In the form including the sealing resin, when using a fastening member such as a bolt as a fixing member that integrates the bottom plate part 40 and the side wall part 41, if a form including a sealing material (not shown) is used, The sealing resin can be prevented from leaking from between the bottom plate portion 40 and the side wall portion 41. In the case where an adhesive is used for the fixing member to be integrated, since the space between the bottom plate portion 40 and the side wall portion 41 can be sealed by this adhesive, the sealing material can be omitted.

≪Manufacture of reactors≫
Reactor 1 having the above configuration is, for example, assembly preparation, side wall preparation, bottom plate preparation (including roughening treatment) ⇒ assembly arrangement ⇒ integration of bottom plate and side wall (⇒ It can be manufactured by a process of filling the sealing resin.

[Preparation of union]
First, a procedure for producing the combination 10 of the coil 2 and the magnetic core 3 will be described. Specifically, as shown in FIG. 3, the core piece 31m and the gap material 31g are laminated to form the inner core portion 31, and the peripheral wall portion 51 of the insulator 5 is disposed on the outer periphery thereof, and the coil elements 2a and 2b are arranged. insert. Here, the inner core portion 31 is used in which an adhesive tape (not shown) is wound around and integrated with the outer periphery of the laminate of the core piece 31m and the gap material 31g.

  Next, the frame plate portion 52 and the outer core portion 32 are arranged so that the assembly of the coil 2 and the inner core portion 31 is sandwiched between the frame plate portion 52 and the outer core portion 32 of the insulator 5. At this time, the end surface 31e of the inner core portion 31 is exposed from the opening of the frame plate portion 52 and contacts the inner end surface 32e of the outer core portion 32. By this step, the combined body 10 is obtained.

[Preparation of side wall]
A side wall 41 formed in a predetermined shape by injection molding or the like is prepared. Here, as shown in FIG. 2, the terminal fitting 8 and the terminal fixing member 9 are arranged in this order in the concave groove 410c and the bolt 91 is tightened to form the terminal block 410, and the side wall portion 41 including the terminal block 410 is prepared. To do. The terminal fitting 8 can be fixed to the side wall 41 after the case 4 is assembled. As described above, it is also possible to prepare one in which the terminal fitting 8 is integrally formed on the side wall.

[Preparing the bottom plate]
A bottom plate portion 40 is formed by punching a metal plate (in this case, an aluminum alloy plate) as a material into a predetermined shape. In the bottom plate portion 40, at least a region where the bonding layer 42 is provided is roughened. Here, alumite treatment (anodization treatment) was applied to the entire bottom plate portion 40. The metal plate as a material may be roughened in advance and then punched into a predetermined shape.

  A bonding layer 42 having a predetermined shape is formed on one surface of the anodized bottom plate portion 40. Here, the bonding layer 42 (before curing) was formed using screen printing. By this step, the bottom plate portion 40 including the anodized layer 43 and the bonding layer 42 is obtained.

[Placement of union]
After the assembled assembly 10 is placed on the bonding layer 42, the assembly 10 is cured while being maintained at a temperature corresponding to the material of the bonding layer 42, and the combination 10 is fixed to the bottom plate portion 40. In particular, in the reactor 1 of the present invention, the surface of the bottom plate portion 40 is subjected to a roughening treatment, so that the constituent material (here, the adhesive) of the treatment region (here, the anodized layer 43) and the bonding layer 42 is obtained. ) Can be sufficiently increased, and the adhesiveness between the two is excellent. Here, by providing an anodized layer 43 having a plurality of fine holes, dimples, and cracks, an anchor effect due to the constituent material of the joining layer 42 allows the bottom plate 40 (anodized layer 43) and the joining layer 42 to be Excellent adhesion. Therefore, the coil 2 (here, the combined body 10) and the bottom plate portion 40 can be firmly adhered to each other through the bonding layer 42.

  In addition, the position of the coil 2 and the outer core portion 32 is fixed by the bonding layer 42, so that the position of the inner core portion 31 sandwiched between the pair of outer core portions 32 is also fixed. Therefore, even when the inner core portion 31 and the outer core portion 32 are bonded with an adhesive, or when the core piece 31m and the gap material 31g are not bonded and integrated with an adhesive or an adhesive tape, the bonding layer 42 The magnetic core 3 including the inner core portion 31 and the outer core portion 32 can be integrated into an annular shape.

[Integration of bottom plate and side wall]
A side wall 41 is placed from above the combined body 10 so as to surround the outer peripheral surface of the combined body 10 and is disposed on the bottom plate part 40. Here, the side wall portion 41 can be disposed at an appropriate position with respect to the bottom plate portion 40 by using the hook-shaped portion of the side wall portion 41 for stopping. Then, as described above, the case 4 is assembled by integrally connecting the bottom plate portion 40 and the side wall portion 41 with bolts or an adhesive. Through this process, the box-shaped case 4 is assembled as shown in FIG. 1, and the combined body 10 can be accommodated in the case 4, and the reactor 1 in a form having no sealing resin. Is obtained. In this embodiment, the end of the winding 2w and the terminal fitting 8 are preferably electrically connected thereafter.

[Filling with sealing resin]
By filling the case 4 with a sealing resin (not shown) and curing, the reactor 1 including the sealing resin can be formed. In this embodiment, the end of the winding 2w and the terminal fitting 8 may be joined after the sealing resin is filled. When the anodized layer 43 such as an alumite layer is provided, depending on the thickness, the crack is generated when the sealing resin is cured, and the constituent material of the bonding layer 42 softened by the heat during the curing is filled in the crack. It can be in the form.

≪Usage≫
The reactor 1 having the above-described configuration is used in applications where the energization conditions are, for example, maximum current (DC): about 100 A to 1000 A, average voltage: about 100 V to 1000 V, and operating frequency: about 5 kHz to 100 kHz, typically electric It can be suitably used as a component part of an in-vehicle power converter such as an automobile or a hybrid automobile.

≪Effect≫
The reactor 1 having the above configuration is a separate member in which the bottom plate portion 40 and the side wall portion 41 are independent, and the bottom plate portion 40 that is in contact with the installation target such as a cooling base is made of a metal material, and the coil 2 is attached to the bottom plate portion 40. Bonded by the bonding layer 42. In particular, in the reactor 1, at least the formation region of the bonding layer 42 in the bottom plate portion 40 is subjected to a roughening treatment (here, including the anodized layer 43), and the surface layer region of the bottom plate portion 40 has fine unevenness. . Therefore, the contact area between the bottom plate portion 40 and the bonding layer 42 is sufficiently large, and the bottom plate portion 40 and the coil 2 can be firmly bonded. Therefore, the reactor 1 can efficiently transfer the heat of the coil 2 to the installation target. Further, if the thickness of the bonding layer 42 is thin and the distance between the coil 2 and the bottom plate portion 40 is short, or the bonding layer 42 is formed of a material having excellent thermal conductivity, the heat of the coil 2 Can be transmitted to the installation target more efficiently. Furthermore, the surface area of the bottom plate portion 40 increases due to the unevenness. From the above, the reactor 1 is excellent in heat dissipation. In particular, in this example, since the material of the bottom plate portion 40 is an aluminum alloy having excellent thermal conductivity, the heat dissipation is further improved.

In addition, the reactor 1 of the first embodiment has the following effects.
(1) In addition to excellent adhesion between the bottom plate portion 40 and the anodized layer 43, and excellent adhesion between the bonding layer 42 and the anodized layer 43, the coil 2 and the bottom plate portion 40 are firmly bonded. be able to.
(2) By providing the anodized layer 43, the insulation (withstand voltage, partial discharge start voltage) can be enhanced.
(3) Since the bottom plate portion 40 and the side wall portion 41 are separate members, the burden associated with the transport of the heavy-weight union 10 when the reactor 1 is assembled is reduced, or the bonding layer is removed with the side wall portion 41 removed. It is excellent in productivity by forming 42 and arranging the union 10.
(4) Since the side wall 41 is made of an insulating resin, it is lightweight.
(5) Since the side wall portion 41 is made of an insulating resin, the coil 2 and the side wall portion 41 can be disposed close to each other, and the size is small.
(6) The space between the coil 2 and the bottom plate portion 40 is small (substantially equal to the total thickness of the bonding layer 42 and the anodized layer 43), and is small.
(7) When the magnetic core 3 is also in contact with the bottom plate portion 40 via the bonding layer 42, heat can be radiated from the magnetic core 3 and the heat dissipation is excellent.
(8) By using a coated rectangular wire for the winding 2w to form an edgewise coil, the contact area between the coil 2 and the bonding layer 42 is sufficiently large, and the heat dissipation is excellent.

(Modification 1)
In the first embodiment, the form in which the bottom plate part 40 is made of a metal material and the side wall part 41 is made of resin has been described. However, both the bottom plate part and the side wall part can be made of a metal material. In this embodiment, since the side wall portion can also be used for the heat dissipation path, heat dissipation can be improved. In this embodiment, when an anodized layer is formed on the inner surface of the side wall, the insulation between the coil and the side wall can be enhanced.

[Test Example 1]
Anodizing treatment (alumite treatment) was performed as the roughening treatment, and the relationship between the roughening treatment and the bonding strength was examined.

  In this test, multiple rod-shaped test pieces (thickness: 0.15 mm, width: 10 mm) made of a rolled material of an aluminum alloy (JIS standard A5052) were prepared, and the test pieces were appropriately anodized to give two bar-shaped test pieces. One end of each is joined with an adhesive to produce a joined test piece. And among the joint test pieces, the load when the both rod-shaped test pieces are peeled by pulling the other end portion of one rod-shaped test piece and the other end portion of the other rod-shaped test piece in the opposite direction (bonding strength) Measure. The test was performed using a commercially available tensile shear tester. For all samples, use a commercially available epoxy adhesive (with filler), apply this adhesive to one end of one bar-shaped test piece, and then bond one end of the other bar-shaped test piece before curing. did. The curing conditions were the same for all samples (140 ° C. × 1.5 hours).

  The joining test piece of sample No. 100 is a sample in which neither of the two bar-shaped test pieces is subjected to an alumite treatment. Both of the bonded test pieces of Samples Nos. 1-1 and 1-2 are samples in which the entire bar-shaped test piece is subjected to an alumite treatment. In the anodizing treatment, the thickness was varied by changing the treatment time (energization time) using known conditions. Specifically, the processing time for Sample No. 1-2 was lengthened. The thickness of the anodized layer (alumite layer) is an average thickness obtained by observing the cross section with an optical microscope or a scanning electron microscope after anodizing and using this observation image.

  As shown in Table 1, it can be seen that Sample No. 1-2, in which the anodized layer is thick, has high bonding strength.

  Fig. 5 (A) is a SEM photograph of the surface of the bar-shaped specimen used in Sample No. 1-2, and Fig. 5 (B) is a SEM of the surface of the bar-shaped specimen used in Sample No. 100. It is a photograph. When alumite treatment is applied as shown in Fig. 5 (A), the surface has a plurality of dimples (here, diameter: about 5μm to 15μm) and very fine micropores, and has an uneven shape. I understand. On the other hand, FIG. 5 (B) shows that although the streak-like rolling traces are visible, the rolling traces are shallow and have substantially no unevenness. From this, it is considered that the surface of Sample No. 1-2 has a fine uneven shape due to the alumite treatment, and the contact area with the adhesive is sufficiently large, so that the bonding strength can be improved. In Sample No. 1-2, the thickness of the anodized layer is sufficiently thick as 10 μm or more, so that the depth of the micropores is sufficiently deep, and the micropores are filled with an adhesive, It is thought that the joint strength was increased by the anchor effect.

  Further, after separately preparing the test specimens of sample Nos. 1-1 and 1-2 as described above, the adhesive adhered to the surface of the rod-shaped test specimen is removed, and the surface of each sample is scanned. Electron microscope: Observed by SEM, it was confirmed that Sample No. 1-2 had a plurality of cracks (those that looked like streaks) as shown in FIG. 6 (A). In particular, in the photograph of FIG. 6 (A), it was confirmed that a long crack having a length of millimeter order was present and that a crack was present in a mesh shape. When the crack portion was further enlarged and observed, it was confirmed that the adhesive had leaked from the crack portion as shown in FIG. 6 (B). From this, it can be said that the crack is filled with an adhesive. Sample No. 1-2 has a crack part filled with an adhesive. On the other hand, no crack was confirmed in Sample No. 1-1.

  Furthermore, when the thickness of the anodized layer was changed to 9 μm and the thickness of the anodized layer was 9 μm or more, the heat treatment was performed under the same conditions as the above-described curing conditions, and the presence or absence of cracks was examined in the same manner. Was sufficiently present, and when it was less than 6 μm, it was confirmed that there were few or no cracks. From this, it is considered that cracks in the anodized layer are caused by the thermal history after the anodizing treatment. Moreover, it can be said that this crack is likely to occur when the anodic oxide layer is thick to some extent even if the thermal history is the same.

  From this test, in sample No. 1-2, in addition to the anchor effect based on fine irregularities formed by anodizing treatment, the anodized layer is thick and cracks formed by thermal history also cause the adhesive and It is considered that the bonding strength could be improved by increasing the contact area.

  Furthermore, when the same test was performed by replacing the adhesive with a commercially available sheet-like adhesive (epoxy resin), the bonding strength (average) in the tensile shear test was 20 MPa or more, and the bonding strength was further increased. . From this, it can be said that the bonding strength can be further increased depending on the type of the adhesive.

[Test Example 2]
The reactor of Embodiment 1 was prototyped and the joining state between the bottom plate and the joining layer was examined.

  In this test, a plate made of a rolled material of an aluminum alloy (JIS standard A5052) was prepared as the bottom plate. The bottom plate is subjected to anodization treatment (alumite treatment) as a roughening treatment to form an anodized layer having a thickness of 12 μm, and then the epoxy adhesive used in Test Example 1 (with filler) is applied, An assembly of a coil and a magnetic core was placed on the adhesive, and the adhesive was cured. The curing conditions were the same as in Test Example 1 (140 ° C. × 1.5 hours). By this step, a bonding layer composed of the adhesive was formed. In this test, the side wall was omitted.

  A cross section of the obtained prototype reactor was taken, and the region where the laminated state of the bottom plate portion, the anodized layer, and the bonding layer was observable was taken as an observation field, and the observation field was observed with a scanning electron microscope: SEM. As a result, it was confirmed that cracks existed from the surface of the anodized layer toward the constituent metal of the bottom plate portion, as shown in the white dotted rectangular frame in FIG. 7 (A). Further, as shown in an enlarged view in FIG. 7 (B), it was confirmed that this crack was filled with an adhesive constituting the bonding layer.

  Therefore, from Test Examples 1 and 2, when the roughening treatment is anodizing, the anode layer is thickened (preferably 9 μm or more, particularly 12 μm or more) and subjected to an appropriate thermal history. It was confirmed that a crack extending from the surface of the oxide layer to the bottom plate portion can be formed. In addition to the fine holes and dimples provided in the anodized layer, a reactor having a plurality of cracks filled with the material constituting the joining layer has a sufficient area for joining the anodized layer and the joining layer. It was confirmed that the coil and the bottom plate portion of the case were sufficiently adhered to each other by the anchor effect by the crack portion filled with the constituent material of the bonding layer, and the bonding strength was high.

[Test Example 3]
The relationship between the anodized layer and the insulating properties was investigated.

  As a comparative sample, a rolled plate of aluminum alloy (JIS standard A5052) was prepared. An insulating sheet (commercially available polyimide film (thickness: 0.025 mm)) is placed on the surface of this comparative sample, an electrode is further placed on the insulating sheet, and the electrode and the rolling plate of the comparative sample are connected to a power source. The partial discharge start voltage was measured. As a result, it was about 690V to 705V.

  On the other hand, a rolled plate of aluminum alloy (JIS standard A5052) was prepared as sample No. 3-1, and an anodic oxide layer having a thickness of 12 μm was formed on a part of the surface of this rolled plate in the same manner as in Test Example 2. did. On this anodized layer, the same insulating sheet as the comparative sample: a polyimide film is arranged, and further an electrode is arranged on the insulating sheet, and the electrode and the anodized layer in the rolled plate of sample No. 3-1 are arranged. The part which was not formed was connected to a power source, and the partial discharge start voltage was measured. As a result, it was about 760V to 780V.

  From this test, it was confirmed that the surface-roughening treatment was anodizing treatment and an anodized layer was provided so that the electrical insulation was excellent.

Embodiment 2
The reactor according to the first embodiment and the first modification can be used, for example, as a component part of a converter mounted on a vehicle or the like, or a component part of a power conversion device including the converter.

  For example, a vehicle 1200 such as a hybrid car or an electric car is used for traveling by being driven by a main battery 1210, a power converter 1100 connected to the main battery 1210, and power supplied from the main battery 1210 as shown in FIG. Motor (load) 1220. The motor 1220 is typically a three-phase AC motor, which drives the wheel 1250 when traveling and functions as a generator during regeneration. In the case of a hybrid vehicle, the vehicle 1200 includes an engine in addition to the motor 1220. In FIG. 8, although an inlet is shown as a charging location of the vehicle 1200, a form including a plug may be adopted.

  The power conversion device 1100 includes a converter 1110 connected to the main battery 1210 and an inverter 1120 connected to the converter 1110 and performing mutual conversion between direct current and alternating current. Converter 1110 shown in this example boosts the DC voltage (input voltage) of main battery 1210 of about 200 V to 300 V to about 400 V to 700 V and feeds power to inverter 1120 when vehicle 1200 is traveling. In addition, converter 1110 steps down DC voltage (input voltage) output from motor 1220 via inverter 1120 to DC voltage suitable for main battery 1210 during regeneration, and causes main battery 1210 to be charged. The inverter 1120 converts the direct current boosted by the converter 1110 into a predetermined alternating current when the vehicle 1200 is running and supplies power to the motor 1220. During regeneration, the alternating current output from the motor 1220 is converted into direct current and output to the converter 1110. doing.

  As shown in FIG. 9, the converter 1110 includes a plurality of switching elements 1111, a drive circuit 1112 that controls the operation of the switching elements 1111, and a reactor L, and converts input voltage by ON / OFF repetition (switching operation). (In this case, step-up / down pressure) is performed. For the switching element 1111, a power device such as FET or IGBT is used. The reactor L has the function of smoothing the change when the current is going to increase or decrease by the switching operation by utilizing the property of the coil that tends to prevent the change of the current to flow through the circuit. The reactor L includes the reactor of the first embodiment and the first modification. By providing the reactor 1 having excellent heat dissipation, the power conversion device 1100 and the converter 1110 also have excellent heat dissipation.

  Vehicle 1200 is connected to converter 1110, power supply converter 1150 connected to main battery 1210, sub-battery 1230 as a power source for auxiliary devices 1240, and main battery 1210. Auxiliary power converter 1160 for converting high voltage to low voltage is provided. The converter 1110 typically performs DC-DC conversion, while the power supply device converter 1150 and the auxiliary power supply converter 1160 perform AC-DC conversion. Some converters 1150 for power feeding devices perform DC-DC conversion. The reactor of the power supply device converter 1150 and the auxiliary power supply converter 1160 has the same configuration as the reactor of the first embodiment and the first modification, and can use a reactor whose size and shape are appropriately changed. . The reactor of the first embodiment can also be used for a converter that performs input power conversion and that only performs step-up or a step-down operation.

  Note that the present invention is not limited to the above-described embodiment, and can be modified as appropriate without departing from the gist of the present invention.

  The reactor of the present invention is a configuration of a power conversion device such as an in-vehicle converter (typically a DC-DC converter) and an air conditioner converter mounted on a vehicle such as a hybrid vehicle, a plug-in hybrid vehicle, an electric vehicle, or a fuel cell vehicle. It can utilize suitably for components.

1 Reactor 10 Union
2 Coil 2a, 2b Coil element 2r Coil connection part 2w Winding
3 Magnetic core 31 Inner core 31e End face 31m Core piece 31g Gap material
32 Outer core part 32e Inner end face
4 Case 40 Bottom plate 40i Inner surface 41 Side wall
400,411 Mounting part 400h, 411h Bolt hole 410 Terminal block 410c Concave groove
42 Bonding layer 43 Anodized layer
5 Insulator 51 Peripheral wall 52 Frame plate 52b Partition plate 52p Pedestal
8 Terminal fitting 81 One end
9 Terminal fixing member 91 bolt
1100 Power converter 1110 Converter 1111 Switching element
1112 Drive circuit L Reactor 1120 Inverter
1150 Power supply converter 1160 Auxiliary power converter
1200 Vehicle 1210 Main battery 1220 Motor 1230 Sub battery
1240 Auxiliary 1250 Wheel

Claims (6)

A reactor comprising a coil, a magnetic core in which the coil is disposed, and a case that houses a combination of the coil and the magnetic core,
The case is
A bottom plate portion made of a metal material;
The bottom plate portion is an independent member, and is attached to the bottom plate portion, and surrounds the periphery of the combination.
Provided on the inner surface of the bottom plate portion, and comprising a bonding layer for fixing the coil,
In the inner surface of the bottom plate portion, an anodized layer is provided in a region where at least the bonding layer is provided ,
The anodized layer is
The thickness is 9 μm or more and 20 μm or less,
Having a crack from the surface to the metal material constituting the bottom plate,
A reactor in which the crack portion is filled with a constituent material of the bonding layer . Some of the bottom plate portion, the anodized layer is not provided, it is exposed the metallic material, the exposed portion is a reactor according to 請 Motomeko 1 Ru mounting position der ground wire. The side wall portion, that is composed of an insulating resin 請 Motomeko 1 or reactor according to claim 2. Reactor according to any one of 請 Motomeko 1 to claim 3 Total thickness Ru der less 2mm of the bonding layer. A converter comprising a switching element, a drive circuit that controls the operation of the switching element, and a reactor that smoothes the switching operation, and converts the input voltage by the operation of the switching element,
The reactor, reactor der Turkey converter according to any one of claims 1 to 4. A converter for converting an input voltage, and an inverter connected to the converter for converting between direct current and alternating current, and for driving a load with electric power converted by the inverter,
The converter, Oh Ru power converter in the converter according to claim 5.